November 2016 Bulletin

Wave-Dominated Shoreface Systems in the Lower Luling Sand, Northern Bee County, South Texas

William A. Ambrose and HongliuZeng

Abstract

The Luling Sand in northern Bee County, Texas is a composite of a lower, shallow-marine, shoreface system truncated by an upper incised-valley-fill fluvial system. The lower Luling Sand consists of barrier-core and barrier-margin (backbarrier) deposits in a wave-dominated shoreline setting. Modern depositional analogs for wave-dominated coastal deposits in lower Luling Sand core include the wave-dominated, microtidal, and transgressive shoreline near the Santee Delta and Cape Romain in South Carolina, where the sandy coastline pinches out landward into muddy backbarrier and transgressive washover-fan and destructional-beachfacies. Differences between sandstone-body geometry and architecture between the upper and lower Luling Sand are a function of unique depositional origin and have implications for future reservoir development in northern Bee County and adjacent areas in south-central Texas. Detailed knowledge of sandstone-body geometry and reservoir continuity in each system (fluvial versus shallow-marine, upper versus lower Luling Sands, respectively) can be used for strategically targeting additional areas for infill and stepout wells where combination structural-stratigraphic traps may exist.